1. Field of the Invention
The present invention relates to a transformed cell with enhanced sensitivity to an antifungal compound and use thereof.
2. Description of the Related Art
It is known that, when a fungicide containing a dicarboxyimide antifungal compound, an “aromatic hydrocarbon antifungal compound” or a phenylpyrrole antifungal compound as an active ingredient is acted on a certain plant-pathogenic filamentous fungus, glycerol synthesis in a cell is stimulated in the fungus like as when undergoes high osmotic stress, and the fungus can not control an intracellular osmolarity, leading to death. From such the activity to the plant-pathogenic filamentous fungus, a protein in a signal transduction system which is involved in osmolarity response was predicted as a target protein of an antifungal compound contained in these fungicides as an active ingredient.
In Neurospora crassa exhibiting sensitivity to the aforementioned antifungal compound, an osmosensitive mutant os-1 was reported. This mutant os-1 exhibited resistance to the aforementioned antifungal compound and, by analysis of the mutant, an os-1 gene which is an osmosensing histidine kinase gene was isolated as a causative gene. A protein having an amino acid sequence encoded by a nucleotide sequence of this os-1 gene was a protein which has a structure of histidine kinase of a two-component regulatory system and, at the same time, has a characteristic region (hereinafter, referred to repeat sequence region in some cases) in which amino acid sequences composed of about 90 amino acids and having homology to each other are present repetitively about 6 times (see, for example, U.S. Pat. No. 5,939,306; Genebank accession U50263, U53189, AAB03698, AAB01979; Alex, A. L. et al., Proc. Natl. Acd. Sci. USA 93:3416-3421; Schumacher, M. M. et al., Current Microbiology 34:340-347; Oshima, M. et al., Phytopathology 92 (1):75-80; Fijimura, M. et al., J. Pesticide Sci. 25:31-36). A gene having homology to the os-1 gene was also isolated from plant-pathogenic filamentous fungus such as Botryotinia fuckeliana, Magnaporthe grisea, Fusarium solani and the like, and its nucleotide sequence and an amino acid sequence encoded by the gene are published. It is known that genes having homology with the os-1 gene are specifically present in filamentous fungus among eukaryotic organisms (see, for example, GeneBank accession AF396827, AF435964, AAL37947, AAL30826; Fujimura, M. et al., Pesticide Biochem. Physiol. 67:125-133; GeneBank accession AB041647, BAB40497).